Clearly, most personality disorders develop over the course of Childhood, adolescence and young adulthood. Although these disorders are often associated with serious impairment, an empirical basis for theories about influences on their incidence and course is only beginning to accumulate. The proposed study extends a longitudinal study of about 800 persons who have been studied since 1975, and who will be an average age of 31 in 2000. The cohort was originally randomly sampled, and has remained Closely representative of the population from which it was sampled. Uniquely, personality disorders (PDs) have been assessed since early adolescence, in conjunction with the Axis I disorders, a broad range of risks, and outcomes. PDs have been shown to be related to a number of childhood risks and1 in turn, to constitute a risk for both adult Axis I disorders and for impairment in function. Our first aim is to identify influences on the course of PDs in the adult years. We will investigate whether the decline in PD symptoms shown in earlier age groups will have leveled off by the late 20's and which risk and protective factors assessed during childhood and adolescence continue to have effects on new onset PD or symptom persistence in middle adulthood. A second aim is to continue our investigation of the connection between Axis disorders (assessed with the CIDI) and PD, examining the extent to which comorbidity may be due to shared risks or due to the prior influence of one kind of disorder on another. We will also investigate the impact of PD on adult function, and on the attainment of socioeconomic level, as well as the independence of these effects from those of comorbid Axis I disorder. Finally, we will investigate the impact of PD on parenting and offspring emotional and behavioral problems.